Increased apoptosis in HepG2.2.15 cells with hepatitis B virus expression by synergistic induction of interferon‐γ and tumour necrosis factor‐α

Background: Interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) were thought to be important immune mediators in host defence against hepatitis B virus (HBV) infection. Aims: To examine the synergistic effect of IFN‐γ and TNF‐α on HBV‐expressing HepG2.2.15 cells and its potential mechanisms. Methods: Cell viability was quantitatively measured by 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide assay. Cell morphology was captured using light microscopy. The typical DNA ladder test was performed using agarose gel electrophoresis. HBsAg and HBeAg titre changes were quantified by the enzyme‐linked immunosorbent assay method. Gene expression was analysed using cDNA macroarrays. Results: Interferon‐γ (1000 U/ml) alone or combined with TNF‐α (5 ng/ml) treatment resulted in apoptosis in HepG2.2.15 cells, but no significant apoptosis in the parent non‐virus expressing HepG2 cells. IFN‐γ‐ and TNF‐α‐mediated apoptosis was reduced by lamivudine treatment in HepG2.2.15 cells. IFN‐γ combined with TNF‐α reduced the titre of hepatitis B surface antigen and hepatitis B e antigen in the HepG2.2.15 cell line. For apoptosis‐related gene changes, IFN regulatory factor 1 (IRF‐1) (12.2‐fold), c‐myc (V00568 4.7‐fold, L00058 2.4‐fold) and caspase 7 (2.3‐fold) genes were upregulated in the combination treatment group. Conclusion: Interferon‐γ and TNF‐α play a role in the cell death of HBV‐expressing HepG2.2.15 cells. Expression of HBV leads to IFN‐γ‐ and TNF‐α‐mediated apoptosis in the cells. Increased IRF‐1, c‐myc and caspase 7 gene expression may be responsible for the synergistic induction of apoptosis by IFN‐γ and TNF‐α.     

Experience of antitumor necrosis factor‐α therapies in Taiwan

Background: Etanercept (Enbrel), was the first approved biologics in Taiwan for rheumatoid arthritis (RA), juvenile RA (JRA), psoriatic arthritis and ankylosing spondylitis. Approximately 500 patients with RA were under etanercept therapy by April 2006. Aim: We aimed to review the current status of biological agents use in the treatment of rheumatic diseases in Taiwan. Methods: MEDLINE database (January 1966 to February 2006) was searched by MeSH terms, limited to Taiwan by author affiliations. All known principal clinical investigators and pharmaceutical companies in Taiwan were contacted for unpublished information about this issue. Results: Six articles including two clinical trials, two case series and two preclinical studies were found in MEDLINE since January 1966. A 12‐week double‐blind placebo‐controlled study of 58 patients with active adult RA in Taiwan revealed better efficacy than results in Western countries. For JRA, two studies reported good results in polyarticular type JRA but fair response in systemic type. Adalimumab (Humira, Abbott) and Alefacept (Ameviev, Biogen) had completed their local trials in RA and psoriasis but they are not yet available in Taiwan. Widespread usage of biologics has been limited due to restricted insurance coverage policy only to the refractory patients with RA. Some herbs demonstrating TNF‐α inhibition properties are under exploratory clinical trials. Conclusions: Etanercept showed better efficacy in patients with adult RA in Taiwan than Western countries. Some herbs demonstrated TNF‐α inhibition and are under laboratory and clinical investigations.     

Inhibition of hepatic tumour necrosis factor‐α attenuates the anandamide‐induced vasoconstrictive response in cirrhotic rat livers

Background: Increased anandamide, an endocannabinoid that interacts with both cannabinoid CB₁ and CB₂ receptors, can induce hepatic vasoconstrictive responses that contribute to the increased intrahepatic resistance (IHR) in cirrhotic rats. Chronic endotoxaemia and the subsequent release of tumour necrosis factor‐α (TNF‐α) are suggested to result in increased anandamide in cirrhotic livers. Thalidomide, which inhibited TNF‐α effectively, has been used clinically in states of chronic TNF‐α elevation with encouraging results. Aims: This study explores the possible effects of thalidomide on hepatic endocannabinoids and microcirculation of cirrhotic rats. Methods: Portal venous pressure (PVP), superior mesenteric arterial blood flow (SMA BF), hepatic TNF‐α, interleukin (IL‐6), protein expression of CB₁ and CB₂ receptor and thromboxane synthase (TXS) were measured in bile duct‐ligated (BDL) rats receiving 1‐month of vehicle (BDL‐V) or thalidomide (BDL‐thalido). The degree of hepatic fibrosis was also assessed. In the liver perfusion system, IHR and concentration–response curves of the portal perfusion pressure to anandamide were evaluated. Results: In BDL‐thalido rats, PVP, IHR and hepatic levels of TNF‐α and IL‐6, protein expression of CB₁ receptors, TXS and hepatic fibrosis were lower than in BDL‐V rats. In BDL‐thalido rat livers, the attenuation of the vasoconstrictive response to anandamide was associated with an upregulation of the CB₂ receptor and a downregulation of the CB₁ receptor. Nevertheless, SMA BF was not different between BDL‐thalido and BDL‐V rats. Conclusions: Thalidomide decreased the PVP and IHR through the attenuation of anandamide‐induced constrictive response, decreasing the production of TNF‐α, IL‐6 and TXA₂ in the liver and the suppression of hepatic fibrogenesis of rats with biliary cirrhosis of this study.     

Adverse effects of tumour necrosis factor‐α blocking agents

Tumor necrosis factor α (TNF‐α) blocking agents have been proved to be very effective in the treatment of various inflammatory rheumatic diseases which are refractory to conventional disease‐modifying antirheumatic drugs. However, anti‐TNF‐α therapy may have adverse effects on host defence against infectious agents in which TNF‐α plays a pivotal role. In addition, there are reports about neurologic, autoimmune, cardiac, and malignant diseases associated with TNF‐α blocking agents. This article summarizes the adverse effects and safety of these agents.     

Effect of interferon α, γ, and tumor necrosis factor α on the HLA-A,B, C expression of cell lines derived from human liver

ABSTRACT— Our study was undertaken to determine whether human recombinant interferon α(rIFNα), γ(rIFNγ), and tumor necrosis factor α(rTNFα) exert an effect on the HLA-A, B, C expression of human liver cell lines. The HLA-A, B, C expression was assayed by immunoperoxidase staining and enzyme-linked immunosorbent assay. rIFNα and γ enhanced the HLA-A, B, C expression of the three cell lines tested, Chang cells, SK-Hep-1, and PLC/PRF/5. The activity of rIFNγ proved more than 8000 times more potent than that of rIFNα in Chang cells, 30 times in SK-Hep-1, and 20 times in PLC/PRF/5, respectively. rTNFα also enhanced the HLA-A, B, C expression of the three cell lines. The enhancement of HLA-A, B, C expression by rIFNα and γ reached a peak on day 3, and that by rTNFα on day 5. These findings suggest that IFNα, IFNγ, and TNFα may play similar roles in enhancement of HLA-A, B, C expression of hepatocytes in hepatitis and hepatoma cells.     

Extended indications for anti‐tumor necrosis factor‐α therapy

Tumour necrosis factor‐α is a pleiotropic cytokine which has a broad range of actions in inflammation, infection and immunity. TNF‐α is supposed to play a crucial role in the pathogenesis of various autoimmune diseases. TNF‐α blocking agents have been demonstrated to be highly effective in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and juvenile rheumatoid arthritis. TNF‐α inhibitors also have been tried with other rheumatic diseases and have emerged as promising treatments. We here review the current evidences of effectiveness of the anti‐TNF‐α therapy in various autoimmune diseases.     

Serum levels of tumor necrosis factor‐α correlate with severity of hepatic encephalopathy due to chronic liver failure

Background: Several studies have shown that serum levels of tumor necrosis factor‐α (TNF) are significantly elevated in patients with acute and chronic liver diseases, where these elevations are independent of the etiology of the underlying disease. Serum levels of TNF are significantly higher in patients with cirrhosis than in those without cirrhosis, reaching the highest levels in decompensated cirrhosis. It has also been shown that plasma levels of TNF correlate with the severity of hepatic encephalopathy (HE) in fulminant hepatic failure. However, still there are no published data regarding the relationship between blood levels of TNF and the presence or severity of HE in patients with chronic liver failure. Aim: The aim of this study is to determine the relationship between serum levels of TNF and clinical grades of HE in patients with liver cirrhosis. Methods: Using a commercially available high‐sensitivity enzyme‐linked immunosorbent assay kit, serum levels of TNF were measured in 74 patients with liver cirrhosis in various clinical grades of HE (grades 0–4). Results: The mean±SEM values of serum levels of TNF at presentation in patients with grade 0 of HE (n=23), grade 1 (n=12), grade 2 (n=14), grade 3 (n=16), and grade 4 (n=9) were 4.50±0.46, 9.10±1.0, 12.98±1.22, 21.51±2.63, and 58.26±19.7 pg/ml, respectively. A significant positive correlation was found between serum levels of TNF and the severity of HE (P<0.0001). Conclusion: Serum levels of TNF correlate positively with the severity of HE in patients with chronic liver failure.     

Interferon γ modulates production of interleukin 1 and tumor necrosis factor by murine Kupffer cells

ABSTRACT— When mononuclear phagocytes, including Kupffer cells, are activated by various agents, they synthesize and release cytokines such as interleukin 1 (IL-1) and tumor necrosis factor (TNF). In this study, we examined the effect of in vitro Kupffer cell activation by recombinant murine interferon γ (IFNγ) on IL-1 and TNF secretion. IFNγ enhanced TNF production in the presence or absence of lipopolysaccharide (LPS), but suppressed IL-1 production by Kupffer cells. Because IFNγ also stimulated prostaglandin E₂ (PGE₂) production, the effect of indomethacin, which is an inhibitor of cyclooxygenase and which inhibits PGE₂ biosynthesis, on IL-1 and TNF production by Kupffer cells was examined. As a result, indomethacin enhanced TNF production by Kupffer cells, but had no effect on IL-1 synthesis. These results suggested that IFNγ modulates the production of IL-1 and TNF by Kupffer cells through different mechanisms.     

Prognostic value of hypoxia inducible factor 1α in esophageal squamous cell carcinoma

Hypoxia inducible factor 1α (HIF 1α) plays a major role in the pleitropic response observed secondary to hypoxic conditions in tumors. Its expression in the tumor cells has been correlated to tumor aggressiveness and prognosis in squamous cell carcinoma (SCC) of the esophagus in Far Eastern population, but limited information is available on the prognostic role of HIF 1α in SCC of esophagus in European population. This information may help in choosing appropriate therapeutic strategies and possibly developing a monoclonal antibody with therapeutic potential targeting the HIF 1α. Tumor samples from 36 patients diagnosed with SCC of the esophagus were collected. Prepared tissue sections were stained with validated and specific monoclonal antibodies for HIF 1α and the expression was correlated with the disease pattern and survival. Out of 36 patients, 17 patients showed low and 19 high expression of HIF 1α. There was no difference in the disease‐free and overall survival between these two groups (P > 0.05, log rank test). Regression analysis showed that HIF 1α was not an independent prognostic factor for survival (P > 0.05). HIF 1α did not show prognostic value in SCC of the esophagus in our study on European population, in agreement with previous studies. Novel strategies on the therapeutic manipulation of HIF 1α in cancer are to be explored further and may have a role to play in improving treatment outcome.     

Tumour necrosis factor‐α promoter region polymorphisms affect the course of spontaneous HBsAg clearance

Background: This study aimed to investigate the roles of tumour necrosis factor‐α (TNF‐α) gene polymorphisms in the spontaneous clearance of HBsAg after a hepatitis B virus (HBV) infection. Methods: Polymorphisms in the TNF‐α (?1031 T to C, ?863 C to A, ?857 C to T, ?308 G to A and ?238 G to A transition) gene were evaluated in 274 chronic HBV‐infected patients and 194 patients with resolved HBV infection. The peripheral blood mononuclear cells (PBMC) isolated from 77 (28%) of the 274 chronic HBV‐infected patients with negative HBeAg and positive antibody to HBeAg were stimulated with HBcAg. Data on TNF‐α genotypes and phenotypes in subjects with/without the A allele at the TNF‐α?863 promoter single nucleotide polymorphism (rs1800630) were compared. Results: The A allele in the ?863 promoter region of the TNF‐α gene was present in 154 (56.2%) chronic HBV‐infected patients and 87 (44.8%) patients who recovered from HBV infection (odds ratio 1.58; P<0.01). The TNF‐α?863 A allele genotype predicted lower TNF‐α production by PBMC after in vitro HBcAg stimulation (P<0.02). Conclusions: The A allele at the ?863 locus of the promoter region of the TNF‐α gene predicts lower HBcAg‐inducible TNF‐α secretion. It is also associated with chronicity of HBV infection.     

Role of serum soluble Fas/soluble Fas ligand and TNF‐α on response to interferon‐α therapy in chronic hepatitis C

Abstract: Aims/Background: To determine the relationship between host factors and host response to interferon (IFN) therapy, serum soluble Fas (sFas), soluble Fas ligand (sFas ligand), and tumor necrosis factor‐α (TNF‐α) were analyzed in 41 patients with chronic hepatitis C (CH‐C) treated with IFN‐α. Methods: Serum levels of sFas, sFas ligand, and TNF‐α were measured at 0, 4, and 24 weeks of IFN therapy. Results: Eighteen patients were complete responders (CR) and 23 patients were non‐responders (NR). Serum levels of sFas and TNF‐α in patients with CH‐C were significantly higher than those in healthy controls (p<0.01 and p<0.01, respectively). Serum sFas ligand levels were significantly lower in CH‐C patients than in healthy controls (p<0.01). Before IFN therapy, serum levels of sFas in NR were significantly higher than those in CR (p<0.05). At 4 weeks of IFN therapy, serum levels of sFas of CR were significantly elevated compared with levels before IFN therapy (p<0.05). Serum levels of sFas correlated with the histological activity of the liver (p<0.05) and alanine aminotransferase (p<0.05). None of the three parameters, serum sFas, sFas ligand, or TNF‐α levels, correlated with each other, with HCV‐RNA genotype or with serum HCV‐RNA load. Multiple logistic regression analysis showed that serum sFas levels before IFN therapy were a contributive factor to predict efficacy of IFN therapy. Conclusions: Serum sFas/sFas ligand and TNF‐α play a possible role in pathogenesis of CH‐C and also in IFN therapy. Serum sFas levels before IFN therapy may be one of the host‐related factors used for evaluating the response of CH‐C patients to IFN therapy.